(i) Field of the Invention
The present invention relates to a two-cylinder type two-stage compression rotary compressor, and more particularly to a two-cylinder type two-stage compression rotary compressor having two cylinders on both sides of, e.g., an intermediate partition plate.
(ii) Description of the Related Art
Conventionally, in this type of rotary compressor, when a refrigerant having a large difference between a high pressure and a low pressure, for example, carbon dioxide (CO.sub.2) is used, a refrigerant pressure reaches approximately 100 kg/cm.sup.2 G on a high pressure side (high stage side), whilst it is approximately 30 kg/cm.sup.2 G on a low pressure side (low stage side). As a result, a difference between a high pressure and a low pressure becomes as large as approximately 70 kg/cm.sup.2 G.
Therefore, when a cross-sectional shape of a connecting portion for connecting two eccentric portions provided to a rotating shaft of a two-cylinder type two-stage compression rotary compressor with a phase difference of 180.degree. is a circular form coaxial with the both eccentric portions, the cross-sectional area which can be physically assured becomes small. Thus, in case of the above-described refrigerant having a high working pressure, i.e., the carbon dioxide (CO.sub.2), a large difference between a high pressure and a low pressure increases a burden imposed on the rotating shaft, which involves such a problem as that the rotating shaft is apt to be elastically deformed.
When the rotating shaft is elastically deformed in this manner, one side of the rotating shaft is brought into contact with a bearing portion to cause an abnormal abrasion to reduce the durability, and vibrations or noises are also generated.